Korg Nutube B1
** The B1K B1K Pre-Order has now completed and we have a limited number of left over units available for sale. **
At the Burning Amp Festival in 2017 Nelson presented a pre-amp using the Korg Nutube dual triode. The latest revision of the circuit available is now available complete with Fairchild JFETs and all directly supplied by Nelson Pass.
Please check the following links for more information:
There are 4 elements to building a complete preamplifier. Purchase the elements separately, or all together as a "full kit" bundle for $299. To build a complete preamplifier you will need:
What's in the completion kit?
Everything else you need to complete the project other than 1, 2 and 3 above. It's an assortment of bits and pieces that joins the Nutube, PCB and Chassis together, turning the whole things into a "full kit", hence the name "completion kit".
The included "wall wart" style power adapter supports an input voltage of 90-264V and has a US style plug. If you don't live in the US you will need to obtain a suitable plug adapter.
Discussion threads / Links:
- Technical discussion: B1K main thread
- Build Guide: B1K Build Guide
- Pre-order Q&A (old news) in the B1K pre-order Q&A thread
- Prototype feedback (old news): B1K pioneer batch feedback
- Pre-order status (old news): B1K pre-order status page
What are the chassis specifications?
- Galaxy 230x170 full aluminum chassis, anodized black with white printing
- Internal dimensions 40x210x170mm
- LED hole ø2mm
- Left switch
- Hole ø6.5mm
- 15mm x 15mm square rear recess, 7mm deep
- Right switch
- Hole ø6.5mm
- 15mm x 24mm rectangular rear recess (allows for switch and LED), 7mm deep
- Potentiometer hole ø10mm, with ø32mm round recess in the front ø8mm deep
- Rear RCA holes ø10mm
- Rear power switch hole ø11mm
It was very simple to build. Mostly because of the very good and detailed instructions.
Love the board has test points too ... so its very easy too tune the pots and verify the build.
I like the sound too. A very fun build for me ;)
I was impressed by the quality of the components and the chassis. Nicely done. Putting the kit together is quite straight forward following 6L6's construction guide. No problems. I wouldn't recommend this as an intro electronics, though,
Sound is very neutral with the standard setup. I haven't tried other settings yet.
One issue with the pre-amp is a loud thump when turning it on or off. But this is mentioned in Mr. Pass' original article.
Overall, I am very pleased and am looking forward to using this with a tube amp that I have under construction.
This kit is easy to build. The only issue I had was needing to ground the volume pot. I used rubber mounts for the board, and sound deadening in the chassis. Microphonics are not an issue. It sounds very good.
The B1 preamp kit is very high quality and was an easy build. I’m very impressed with how transparent this preamp is. It’s a great value and the sound far exceeds what one would expect at this price.
Another well constructed kit from the store like ACA. 6L6 instructions are great again and kit contents are meticulously packaged. Customer service is excellent too, helping out with some additional cat 5 that I overstripped.
I only wish this unit could be patched into an existing preamp set up with an on off bypass switch to activate nutube/harmonics and a "volume knob" to dial in bias or amount of distortion. Overall, am a very happy customer. Highly recommended :-). Thank you 6L6!
I built this as a companion to the ACA. Love the sound of the ACA, but it needed a little boost at the front end, so enter the Korg B1. It's not a completely true pass through of the signal, but, set at the recommended level, the harmonics introduced are pleasant to the ear. For the price, I'd highly recommend this as much for it being fun to build, as it is enjoyable to listen to.
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